This invention relates to a defrost heater for a cooling appliance, such as a refrigerator, freezer, or other appliance having evaporating coils which require defrosting.
Cooling appliances, such as refrigerators and freezers, are provided with evaporator coils through which coolant is pumped to cool the refrigerator or freezer cooling chamber. Ambient moisture condenses and freezes on the coils, thereby requiring periodic defrosting. Modern appliances are equipped with automatic defrosting mechanisms, which include a defrost heater mounted adjacent to the coils. The defrost heaters include an electric resistive heating element which is cycled on and off periodically to heat the coils and thereby melt the moisture entrained thereon. Normally, the heating element is mounted below the coils and heat is conducted from the element to the coils by convection.
Common "side by side" refrigerator designs require multiple sets of cooling coils. Often, one set is mounted above another set, and sometimes a third set is mounted parallel to the coils of one of the other sets. Heretofore, multiple sets of coils have required multiple defrost heaters, particularly since heat is transferred by convection; accordingly, for effective cooling, the heater must be relatively close to the coils.